/**
 * redis工具類
 */
@Component
public class RedisService {

    @Autowired
    private RedisTemplate redisTemplate;

    /**
     * 寫入緩存
     * @param key
     * @param value
     * @return
     */
    public boolean set(final String key, Object value) {
        boolean result = false;
        try {
            ValueOperations<Serializable, Object> operations = redisTemplate.opsForValue();
            operations.set(key, value);
            result = true;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return result;
    }


    /**
     * 寫入緩存設(shè)置時(shí)效時(shí)間
     * @param key
     * @param value
     * @return
     */
    public boolean setEx(final String key, Object value, Long expireTime) {
        boolean result = false;
        try {
            ValueOperations<Serializable, Object> operations = redisTemplate.opsForValue();
            operations.set(key, value);
            redisTemplate.expire(key, expireTime, TimeUnit.SECONDS);
            result = true;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return result;
    }


    /**
     * 判斷緩存中是否有對(duì)應(yīng)的value
     * @param key
     * @return
     */
    public boolean exists(final String key) {
        return redisTemplate.hasKey(key);
    }

    /**
     * 讀取緩存
     * @param key
     * @return
     */
    public Object get(final String key) {
        Object result = null;
        ValueOperations<Serializable, Object> operations = redisTemplate.opsForValue();
        result = operations.get(key);
        return result;
    }

    /**
     * 刪除對(duì)應(yīng)的value
     * @param key
     */
    public boolean remove(final String key) {
        if (exists(key)) {
            Boolean delete = redisTemplate.delete(key);
            return delete;
        }
        return false;

    }

}

@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface AutoIdempotent {

}

public interface TokenService {

    /**
     * 創(chuàng)建token
     * @return
     */
    public  String createToken();

    /**
     * 檢驗(yàn)token
     * @param request
     * @return
     */
    public boolean checkToken(HttpServletRequest request) throws Exception;

}

@Service
public class TokenServiceImpl implements TokenService {

    @Autowired
    private RedisService redisService;


    /**
     * 創(chuàng)建token
     *
     * @return
     */
    @Override
    public String createToken() {
        String str = RandomUtil.randomUUID();
        StrBuilder token = new StrBuilder();
        try {
            token.append(Constant.Redis.TOKEN_PREFIX).append(str);
            redisService.setEx(token.toString(), token.toString(),10000L);
            boolean notEmpty = StrUtil.isNotEmpty(token.toString());
            if (notEmpty) {
                return token.toString();
            }
        }catch (Exception ex){
            ex.printStackTrace();
        }
        return null;
    }


    /**
     * 檢驗(yàn)token
     *
     * @param request
     * @return
     */
    @Override
    public boolean checkToken(HttpServletRequest request) throws Exception {

        String token = request.getHeader(Constant.TOKEN_NAME);
        if (StrUtil.isBlank(token)) {// header中不存在token
            token = request.getParameter(Constant.TOKEN_NAME);
            if (StrUtil.isBlank(token)) {// parameter中也不存在token
                throw new ServiceException(Constant.ResponseCode.ILLEGAL_ARGUMENT, 100);
            }
        }

        if (!redisService.exists(token)) {
            throw new ServiceException(Constant.ResponseCode.REPETITIVE_OPERATION, 200);
        }

        boolean remove = redisService.remove(token);
        if (!remove) {
            throw new ServiceException(Constant.ResponseCode.REPETITIVE_OPERATION, 200);
        }
        return true;
    }
}

@Configuration
public class WebConfiguration extends WebMvcConfigurerAdapter {

    @Resource
   private AutoIdempotentInterceptor autoIdempotentInterceptor;

    /**
     * 添加攔截器
     * @param registry
     */
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(autoIdempotentInterceptor);
        super.addInterceptors(registry);
    }
}

/**
 * 攔截器
 */
@Component
public class AutoIdempotentInterceptor implements HandlerInterceptor {

    @Autowired
    private TokenService tokenService;

    /**
     * 預(yù)處理
     *
     * @param request
     * @param response
     * @param handler
     * @return
     * @throws Exception
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {

        if (!(handler instanceof HandlerMethod)) {
            return true;
        }
        HandlerMethod handlerMethod = (HandlerMethod) handler;
        Method method = handlerMethod.getMethod();
        //被ApiIdempotment標(biāo)記的掃描
        AutoIdempotent methodAnnotation = method.getAnnotation(AutoIdempotent.class);
        if (methodAnnotation != null) {
            try {
                return tokenService.checkToken(request);// 冪等性校驗(yàn), 校驗(yàn)通過則放行, 校驗(yàn)失敗則拋出異常, 并通過統(tǒng)一異常處理返回友好提示
            }catch (Exception ex){
                ResultVo failedResult = ResultVo.getFailedResult(101, ex.getMessage());
                writeReturnJson(response, JSONUtil.toJsonStr(failedResult));
                throw ex;
            }
        }
        //必須返回true,否則會(huì)被攔截一切請(qǐng)求
        return true;
    }


    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {

    }

    /**
     * 返回的json值
     * @param response
     * @param json
     * @throws Exception
     */
    private void writeReturnJson(HttpServletResponse response, String json) throws Exception{
        PrintWriter writer = null;
        response.setCharacterEncoding("UTF-8");
        response.setContentType("text/html; charset=utf-8");
        try {
            writer = response.getWriter();
            writer.print(json);

        } catch (IOException e) {
        } finally {
            if (writer != null)
                writer.close();
        }
    }

}

@RestController
public class BusinessController {


    @Resource
    private TokenService tokenService;

    @Resource
    private TestService testService;


    @PostMapping("/get/token")
    public String  getToken(){
        String token = tokenService.createToken();
        if (StrUtil.isNotEmpty(token)) {
            ResultVo resultVo = new ResultVo();
            resultVo.setCode(Constant.code_success);
            resultVo.setMessage(Constant.SUCCESS);
            resultVo.setData(token);
            return JSONUtil.toJsonStr(resultVo);
        }
        return StrUtil.EMPTY;
    }


    @AutoIdempotent
    @PostMapping("/test/Idempotence")
    public String testIdempotence() {
        String businessResult = testService.testIdempotence();
        if (StrUtil.isNotEmpty(businessResult)) {
            ResultVo successResult = ResultVo.getSuccessResult(businessResult);
            return JSONUtil.toJsonStr(successResult);
        }
        return StrUtil.EMPTY;
    }
}